Satellite system architecture for coverage areas of disparate demand

ABSTRACT

Disclosed is a satellite communication system that allocates bandwidth to maximize the capacity of the communication system while providing service to geographical areas having different demands. A smaller portion of the frequency spectrum can be allocated for subscriber beams that supply service to low demand areas. A larger portion of the frequency spectrum can be provided to subscriber beams that provide access to high demand areas. Allocation of bandwidth can be determined by the amount of demand in low demand areas versus the amount of demand in high demand areas. High demand gateways are physically located in low demand subscriber beams, while low demand gateways are physically located in high demand subscriber beams, which prevents interference.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based upon and claims the benefit of U.S.provisional application Ser. No. 61/252,586, filed Oct. 16, 2009, byErwin C. Hudson, entitled “Satellite System Architecture for CoverageAreas of Disparate Demand.” The entire content of this application ishereby specifically incorporated herein by reference for all itdiscloses and teaches.

BACKGROUND OF THE INVENTION

Communication satellites have become extremely important, not only formilitary purposes but also for commercial purposes. Satellites, such asthe WildBlue Communications, Inc. Anik F2 satellite and the WildBlue-1satellite, provide broadband Internet access to numerous subscribersthroughout the satellite coverage area, including subscribers in ruraland remote areas that may be unserved by terrestrial systems.

SUMMARY OF THE INVENTION

An embodiment of the present invention may therefore comprise a methodof providing satellite communication services using an allocatedfrequency spectrum having a predetermined bandwidth in a satellitecommunication system that has multiple beams covering high demand areasand low demand areas comprising: allocating a first percentage of thepredetermined bandwidth as a low demand frequency spectrum for use inlow demand subscriber beams and low demand gateway beams so that the lowdemand area is provided with a low demand subscriber capacity thatcorresponds to the first percentage of the predetermined bandwidthallocated as the low demand frequency spectrum; allocating a secondpercentage of bandwidth as a high demand frequency spectrum for use inhigh demand subscriber beams and high demand gateway beams so that thehigh demand area is provided with a high demand subscriber capacity thatcorresponds to the second percentage of the predetermined bandwidthallocated as the high demand frequency spectrum; directing the lowdemand subscriber beams to the low demand areas; directing the highdemand subscriber beams to the high demand areas; directing the lowdemand gateway beams to low demand gateways located in the high demandareas which reduces interference between the low demand gateway beamshaving the low demand frequency spectrum and the high demand subscriberbeams having a high demand frequency spectrum that is different from thelow demand frequency spectrum; directing the high demand gateway beamsto high demand gateways located in the low demand areas which reducesinterference between the high demand gateway beams, having the highdemand frequency spectrum, and the low demand subscriber beams, having alow demand frequency spectrum that is different from the high demandfrequency spectrum.

The present invention may further comprise a satellite communicationsystem using an allocated frequency spectrum having a predeterminedbandwidth that provides satellite communication services to high demandareas and low demand areas comprising: a plurality of low demandsubscriber beam antennas that direct low demand subscriber beams to lowdemand geographical areas, the low demand subscriber beams using a lowdemand frequency spectrum which is a first percentage of thepredetermined bandwidth; a plurality of high demand subscriber beamantennas that direct high demand subscriber beams to high demandgeographical areas, the high demand subscriber beams using a high demandfrequency spectrum which is a second percentage of the predeterminedbandwidth; at least one low demand gateway beam antenna that directs alow demand gateway beam to a low demand gateway located in the highdemand geographical area to reduce interference between the low demandgateway beam, using the low demand frequency spectrum, and the highdemand subscriber beams, using the high demand frequency spectrum; atleast one high demand gateway beam antenna that directs a high demandgateway beam to a high demand gateway that is located in the low demandgeographical area to reduce interference between the high demand gatewaybeam, using the high demand frequency spectrum, and the low demandsubscriber beams, using the low demand frequency spectrum.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a graphical representation of a typical geographical demanddistribution of satellite communication services for broadband Internetaccess in the United States.

FIG. 1B is a graphical representation of subscriber beams and gatewaysdisposed over the United States for a typical satellite communicationsystem.

FIG. 2 is a graphical representation of an example of subscriber beambandwidth distribution that can be utilized by one or more embodimentsof the present invention.

FIG. 3 is a schematic illustration of one embodiment of a distributionof gateways and subscriber beams for low demand coverage areas and highdemand coverage areas.

FIG. 4A is a graph illustrating frequency band allocation.

FIG. 4B is an additional graph illustrating frequency band allocation.

FIG. 5 is a graph of another embodiment of frequency band allocation.

FIG. 6 is a schematic block diagram of one embodiment of a satellitenetwork.

FIG. 7 is another schematic illustration of an embodiment of a satellitecommunication system.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is a schematic illustration of a typical geographical demanddistribution of subscribers of broadband Internet services provided by asatellite communication system. The geographical demand distribution100, illustrated in FIG. 1, is representative of the geographical demanddistribution of the WildBlue 1 and WildBlue Anik F2 satellites that arecurrently being operated by WildBlue Communications, Inc., 5970Greenwood Plaza Boulevard, Suite 300, Greenwood Village, Colo. 80111. Asillustrated in FIG. 1, there are high demand areas, such as high demandarea 102 in the Eastern United States, and high demand area 104 on theWest Coast of the United States. Low demand area 106 is located in theWestern States of the United States. As used in this patent, “highdemand area” refers to the geographic areas served by a subscriber beamswhere comparatively more bandwidth utilization is desired or intendedthan in other areas (such other areas are referred to as “low demandareas.”). Actual demand is not relevant with respect to the term “highdemand area” or “low demand area,” but rather refers to the desiredbandwidth utilization. The WildBlue 1 satellite and the WildBlue Anik F2satellite utilize a series of subscriber beams, such as subscriber beams108, illustrated in FIG. 1B, that are approximately the same size andcover the entire geographical area of the United States, so that all ofthe geographical area of the contiguous United States has access to theWildBlue satellites. The subscriber beams 108, such as illustrated inFIG. 1B, provide the same access to the low demand area 106 (WesternStates) as the high demand area 102, 104 (Eastern United States and WestCoast).

As also illustrated in FIG. 1B, gateway stations that send and receivemicrowave signals to and from a communication satellite, such asWildBlue 1 and WildBlue Anik F2 satellites, are dispersed throughout theUnited States and communicate with the satellite on a separate set offrequencies from the frequencies that are utilized by the satellite forthe subscriber beams 108. For example, subscriber beams may utilize afirst set of frequencies that may be referred to as frequency “Band A.”The subscriber beams on Band A provide communication between thesubscribers and the satellite. A second set of frequencies, “Band B,” isused to communicate between the satellite and the gateways.Non-overlapping bands of frequencies, i.e., Band A and Band B, are usedto prevent interference between the gateway communication signals andthe subscriber beams, since the gateways are physically located withinthe geographical regions of the subscriber beams. Band A and Band B mayinclude the total frequency spectrum that is allocated by the FederalCommunications Commission or other regulatory authority that can be usedby the satellite for communications to maximize the usage of thesatellite communication system. Because of the high demand for highspeed Internet communications and the limited frequency spectrum that isavailable, there is a limit to the number of subscribers that can belinked to the communication system, especially in high demand areas.

To increase capacity, ViaSat, Inc. has disclosed a satellitearchitecture in U.S. Patent Publication No. U.S. 2009/0081946, publishedMar. 26, 2009 (U.S. application Ser. No. 12/187,051) (the “ViaSat '051patent application”) that discloses a system in which services are onlyprovided to high demand area 102 (Eastern United States) and high demandarea 104 (West Coast), as shown in FIG. 1A. The low demand area 106constitutes approximately 40 percent of the geographical area of thecontiguous United States and the high demand areas 102, 104 constituteapproximately 60 percent of the geographical area of the contiguousUnited States. By eliminating subscriber beam coverage in low demandarea 106, all of the available frequency spectrum, both Band A and BandB, may be used to serve subscribers in high demand areas 102 and 104.Assuming that the allocated Band A and Band B have approximately thesame bandwidth, the approach effectively doubles the satellite capacityin the high demand areas. In addition, with the total subscriber beamcoverage area reduced by 40% by eliminating subscriber beam coverage inlow demand area 106, the satellite transmitter power that would havebeen required to serve low demand area 106 can be redirected toward highdemand areas 102 and 104, resulting in only a modest increase in totalsatellite transmitter power to support twice the total subscribercapacity.

As also disclosed in the ViaSat '051 patent application, the entirefrequency spectrum of Band A and Band B is used for the gateway linkswhich are placed in low demand area 106. Since the gateways are locatedoutside of the geographical area of the subscriber beams, where there isno subscriber service, the gateways can reuse the same frequencyspectrum, in its entirety, as is used for the subscriber beams. Again,assuming that the allocated Band A and Band B have approximately thesame bandwidth, the frequency band of the gateway beams is also doubledusing the ViaSat technique. This reduces the total number of gatewaysrequired by half and, with only half as many gateways required, thegateways can be placed far enough apart within the low demand area toavoid interference between them. This architecture also reduces thetotal cost of the gateways by approximately a factor of 2. However, theViaSat system architecture does not provide service to the low demandarea 106, which comprises approximately 40 percent of the geographicalarea of the United States.

To overcome these disadvantages, FIG. 2 illustrates a subscriber beambandwidth distribution pattern 200 that provides service to the highdemand areas 102, 104, as well as the low demand area 106, asillustrated in FIG. 1A. As shown in FIG. 2, a plurality of high demandsubscriber beams 204 is used to cover the Eastern part of the UnitedStates. Another set of high demand subscriber beams 206 is used to coverthe West Coast region. Low demand subscriber beams 202 are used to coverthe low demand area 106 that comprises the Western states. In oneparticular implementation, a new satellite can be positioned in ageostationary at orbit at 89 degrees west longitude to cover the entire48 contiguous states using a subscriber beam frequency reuse patternhaving the 76 beams illustrated in FIG. 2. Each of the demand bandwidthsubscriber beams 202 is capable of each serving approximately 10,000subscribers while each of the high bandwidth subscriber beams 204 iscapable of serving approximately 30,000 subscribers. A satellite usingthis technology can have a net capacity of greater than 1.5 millionsubscribers.

FIG. 3 illustrates an example of a distribution pattern 300 of gatewaysand subscriber beams that are capable of providing the subscriber beambandwidth distribution 200, illustrated in FIG. 2. As shown in FIG. 3,the high demand coverage area 302 includes a plurality of subscriberbeams, such as high demand subscriber beams 204, illustrated in FIG. 2.Low demand gateways 306 are located in the high demand coverage area302. The low demand gateways 306 use a different frequency than the highdemand subscriber beams so that no interference is created between thesignals transmitted between the low demand gateways 306 and the highdemand subscriber beams, as disclosed in more detail below. Similarly,the low demand coverage area 304 includes a plurality of low demandsubscriber beams, such as low bandwidth subscriber beams 202,illustrated in FIG. 2. Located within the low demand coverage area 304are a plurality of high demand gateways 308. The high demand gateways308 use a different frequency than the low demand subscriber beams sothat no interference is created, as explained in more detail below.

FIG. 4A is a graph 400 illustrating the frequencies of Band A 402 andBand B 404. Band A and Band B are shown as contiguous frequency bands,but may actually be non-contiguous, may be on different polarizations,and may be separated by other frequency bands. As described above, BandA is typically used for subscriber beam communications while Band B istypically used for the gateway communications. As described above withrespect to the ViaSat '051 patent application, Band A and Band B areboth used for subscriber communications and gateway communications byeliminating service to the low demand area 106, illustrated in FIG. 1A,and placing the gateways in the low demand area 106 so that the gatewaysdo not interfere with the subscriber beam communications. Rather thancompletely eliminating service for a particular area and using all ofthe bandwidth of both Band A and Band B, a portion of the bandwidth canbe used for subscriber beams in the low demand area, such as the lowdemand area 106 of the Western states, illustrated in FIG. 1A. Thispercentage of the bandwidth that can be used for the low demand areascan be determined by determining the average demand in those areascompared to the average demand in the high demand areas. For example, ifdemand for the service in the low demand area 106 (Western states) isone-fourth of the demand in the high demand areas 102 and 104, then 20percent of the bandwidth 406 of the total frequency spectrum of Band Aand Band B can be allocated to the low demand subscriber beams, asillustrated in FIG. 4A. The remaining three-quarters of the bandwidth408 of the total frequency spectrum can be allocated for the high demandsubscriber beams, which is eighty percent of the bandwidth. Thefrequency band 406, which is 20 percent of the total bandwidth of Band Aplus Band B, is used for both the low demand subscriber beams 304 (FIG.4), as well as the low demand gateways 306 (FIG. 3), which are locatedin the high population subscriber beam areas. Similarly, the high demandsubscriber beams 302 (FIG. 3) use the frequency spectrum 408 and arelocated in the geographical area of low demand subscriber beams 304(FIG. 3). Although FIG. 4A illustrates the band 406 that is utilized bythe low demand subscriber beams and gateways as the lower portion of thefrequency spectrum of Band A and Band B, the frequency band 406 cancomprise any contiguous portion, as well as any combination ofnon-contiguous portions, of the frequencies and polarizations of Band Aand Band B. The same is also true for frequency band 408.

FIG. 4B is a graph that is similar to the graph of FIG. 4A, except thatFIG. 4B illustrates the four distinct frequency bands (commonly referredto as four “colors”) used by the subscriber beams for both frequencyband 406 and frequency band 408. As shown in FIG. 4B, frequency band 406is divided up into four different frequency bands. The four differentfrequency bands are frequency bands 410 (first color), 412 (secondcolor), 414 (third color) and 416 (fourth color). These frequency bandsare assigned to subscriber beams on an alternating basis so that atleast one beam separation is provided between subscriber beams in thesame band, thereby minimizing interference between subscriber beams.Similarly, frequency band 408 that is used for high populationsubscriber bands, has four different frequency bands, i.e., frequencybands 418 (first color), 420 (second color), 422 (third color) and 424(fourth color). As can be seen from FIG. 4B, a substantially greateramount of frequency spectrum is provided in each of the frequency bands418-424 for the high population subscriber beams, than that provided infrequency bands 410-416, that are used for the low population subscriberbeams. The availability of more frequency spectrum within a subscriberbeam that covers the same size geographical area results in subscriberbeams having a subscriber capacity that increased by the same percentageas the increase in bandwidth allocation. For example, a subscriber beamusing the frequency band 410 can only accommodate one-fourth of thenumber of subscribers as a subscriber band using the frequency band 418,since frequency band 418 has four times the frequency spectrum offrequency band 410.

FIG. 5 is an illustration of another embodiment of a way of dividing thefrequency bands 500. As shown in FIG. 5, Band A 502 and Band B 504comprise the total bandwidth that can be used by the satellite system.As shown in FIG. 5, frequency Band 506 is only 10 percent of the totalfrequency spectrum of Band A 502 plus Band B 504. Frequency band 508 is90 percent of the frequency spectrum of Band A 502 and Band B 504.Frequency band 506 is used for the low demand subscriber beams andgateways located in the high demand subscriber beam areas. Frequencyband 508 is used for the high demand subscriber beams and gatewayslocated in low demand subscriber beam areas. The allocation of bandwidthdisclosed in the embodiment of FIG. 5 may be utilized in instances inwhich demand for the service in the low demand areas is approximately 10percent of the subscriber demand in the high demand areas. In thismanner, nine times the amount of capacity can be provided in the highdemand subscriber beams relative to the low demand subscriber beams.

The frequency allocation of 10 percent and 90 percent, illustrated inFIG. 5, is another example of the manner in which the frequency spectrumof Band A and Band B can be divided. Of course, the frequency spectrumcan be divided in any desired manner based upon demand in low demandareas compared to high demand areas. In this fashion, satellite systemscan be custom designed for geographical areas depending upon demand. Ininstances in which empirical data is not available, demand can bedetermined by population and other demographic information regarding aparticular region. Further, this technique of allocating bandwidth neednot be limited to two demand areas, such as a low demand area and a highdemand area. For example, it may be desirable to allocate the frequencyspectrum between a low demand area, a medium low demand area, a mediumhigh demand area and a high demand area. Gateways can be located insubscriber beam areas that use frequencies that are different from thefrequencies used by the gateway to prevent interference. Any number ofdivisions can be used to achieve desired results. This manner ofallocating bandwidth has advantages over other techniques of usingdifferent size beams to cover greater or lesser geographical areas,which results in other inherent inefficiencies.

FIG. 6 is a schematic illustration of one embodiment of a satellitenetwork 600. As shown in FIG. 6, satellite network 600 includes asatellite 602 that communicates using high demand subscriber beam 652,low demand subscriber beam 664, high demand gateway beam 624 and lowdemand gateway beam 612. Low demand gateway beam 612 communicatesinformation between satellite 602 and antenna 604 that are connected tothe low demand gateway 608. Low demand gateway 608 communicates throughlink 630 to point of presence server 634. The point of presence server634 is linked to network 640, that is connected to the public Internet642. Low demand gateways 608, 610 are two of a number of low demandgateways, as schematically illustrated in FIG. 6. For example, in oneembodiment, eight different low demand gateways, such as low demandgateways 608, 610 are used. Low demand gateway 610 is connected toantenna 606. Satellite 602 communicates with the low demand gateway 610through gateway beam 614. Low demand gateway 610 is also connected tothe POP interface 634 via link 611.

Satellite 602, as shown in FIG. 6, communicates with high demand gateway620 via antenna 616 and high demand gateway beam 624. A plurality ofhigh demand gateways may be provided. For example, in one embodiment,eleven high demand gateways are provided for communicating with thesatellite 602. High demand gateway 622 uses antenna 618 and gateway beam626 to communicate with satellite 602. High demand gateway 620 iscoupled to POP interface 632 via link 628. High demand gateway 622 iscoupled to POP interface 632 via link 623. Other high demand gatewaysare also linked to the POP interface 632. The POP interface 632 iscoupled to network 640 by link 636. Network 640 couples the POPinterface 632 to the public Internet 642. Network operation center 650,illustrated in FIG. 6, is coupled to a POP interface 644 via link 648.Link 646 couples the POP interface 644 to the network 640. The network640 allows communication with each of the gateways that are illustratedin FIG. 6.

Satellite 602, illustrated in FIG. 6, also communicates with high demandsubscribers 656 via high demand subscriber beam 652. Low demandsubscribers 658 communicate with satellite 652 via low demand subscriberbeam 654. The bandwidth of the high demand subscriber beam 652 and lowdemand subscriber beam 654 is allocated in accordance with any desiredallocation, such as described above with respect to FIGS. 4A, 4B and 5.High demand subscriber beams 652 use the larger frequency band, such asfrequency band 408 illustrated in FIG. 4A, and frequency band 508,illustrated in FIG. 5. Low demand subscriber beams 654 use the smallerfrequency bands, such as frequency band 406 illustrated in FIG. 4A, andfrequency band 506, illustrated in FIG. 5. Subscribers 656 are locatedin high demand areas, such as high demand areas 102, 104, illustrated inFIG. 1A. Subscribers 658 are located in low demand areas, such as lowdemand area 106, illustrated in FIG. 1A. Low demand gateways, such aslow demand gateways 608, 610, are physically located in high demandareas, such as high demand areas 102, 104, illustrated in FIG. 1A. Thelow demand gateways beams, such as low demand gateway beams 612, 614,use reduced or narrower frequency bands, such as frequency band 406,illustrated in FIG. 4A, or frequency band 506, illustrated in FIG. 5.High demand gateways 620, 622 are located in low demand areas, such aslow demand area 106, illustrated in FIG. 1A. High demand gateway beams624, 626 use the frequency bands, such as frequency band 408,illustrated in FIG. 4A, and frequency band 508, illustrated in FIG. 5.

FIG. 7 is another schematic illustration of an embodiment of a satellitecommunication system 700. As shown in FIG. 7, the low demand gateway 706is located within the geographical region of high demand subscriber beam702. Similarly, the high demand gateway 708 is located within thegeographical region of low demand subscriber beam 704. The high demandsubscriber beams communicate with the high demand subscriber beamantennas 710 that are located on satellite 726. Information that istransmitted by a subscriber in a high demand subscriber area to thesatellite 726 is received by the high demand subscriber beam antennas710 and transmitted through a wideband return repeater 718, which isconnected to a gateway antenna 716 that is located on the satellite 726.The gateway antenna 716 then transmits a gateway signal to the highdemand gateway 708. High demand gateway 708 transmits data to thegateway antenna 716, located on the satellite 726, which is sent to thewideband forward repeater 720. Wideband forward repeater 720 thentransmits a signal to the high demand subscriber beam antennas 710 thattransmit the information from the high demand gateway 708, on the highdemand subscriber beam 702, to the subscribers in the high demandsubscriber areas.

As also shown in FIG. 7, data from subscribers in low demand subscriberareas is transmitted to the low demand subscriber beam antennas 712which are located on satellite 726. Information received fromsubscribers in the low demand subscriber areas is then transmittedthrough the narrow beam return repeater 722 to gateway antenna 714.Gateway antenna 714 transmits a signal to the low demand gateway 706that is located in the geographical region of the high demand subscriberbeam 702. Information from the low demand gateway 706 is transmittedfrom the low demand gateway 706 to gateway antenna 714. This informationis transmitted through the narrow band forward repeater 724 to the lowdemand subscriber beam antenna 712. Low demand subscriber beam antenna712 transmits a signal via the low demand subscriber beam 704 to thesubscribers in the low demand subscriber area. The wide band repeaters718, 720, as well as the narrow band repeaters 722, 724, arespecifically constructed to receive and transmit information inaccordance with the frequencies and the allocated bandwidth described inFIGS. 4A, 4B and 5.

Hence, a satellite communication system is described in which bandwidthcan be allocated in accordance with demand in certain geographicalareas, which optimizes the efficiency and capacity of a communicationsystem. The communication system can be custom built to accommodatevarious geographical regions, demand distribution and demandpercentages. High efficiency and high capacity of the allocatedbandwidth are provided while simultaneously providing coverage for allgeographical regions.

The foregoing description of the invention has been presented forpurposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise form disclosed, andother modifications and variations may be possible in light of the aboveteachings. The embodiment was chosen and described in order to bestexplain the principles of the invention and its practical application tothereby enable others skilled in the art to best utilize the inventionin various embodiments and various modifications as are suited to theparticular use contemplated. It is intended that the appended claims beconstrued to include other alternative embodiments of the inventionexcept insofar as limited by the prior art.

1-26. (canceled)
 27. A method of allocating system bandwidth resourcesin a satellite communication system comprising a multi-beam satelliteproviding satellite communication services to a service area,comprising: determining a relative bandwidth demand for one or moresubscriber beams serving a first user beam coverage area via themulti-beam satellite; and allocating a first portion of the systembandwidth resources to the one or more subscriber beams in proportion tothe relative bandwidth demand.
 28. The method of claim 27, furthercomprising: dividing the first portion of the system bandwidth resourcesinto a plurality of resource colors; and associating each of the one ormore subscriber beams with a resource color of the plurality of resourcecolors.
 29. The method of claim 27, further comprising: allocating asecond portion of the system bandwidth resources to one or more secondsubscriber beams serving a second user beam coverage area via themulti-beam satellite.
 30. The method of claim 29, wherein the firstportion and the second portion comprise substantially all of the systembandwidth resources.
 31. The method of claim 29, further comprising:allocating a third portion of the system bandwidth resources to one ormore third subscriber beams serving a third user beam coverage area viathe multi-beam satellite.
 32. The method of claim 29, furthercomprising: locating a gateway serving the first user beam coverage areain the second user beam coverage area, the gateway communicating withthe multi-beam satellite via a gateway beam using the first portion ofthe system bandwidth resources.
 33. The method of claim 27, wherein thesystem bandwidth resources comprise one or more contiguous frequencybands.
 34. The method of claim 27, wherein the system bandwidthresources comprise a plurality of non-contiguous frequency bands. 35.The method of claim 27, wherein the system bandwidth resources comprisemultiple polarizations.
 36. The method of claim 27, wherein the relativebandwidth demand is determined based at least in part on empiricaldemand data of the first user beam coverage area and at least one otheruser beam coverage area.
 37. The method of claim 27, wherein therelative bandwidth demand is determined based at least in part ondemographic data of the first user beam coverage area and at least oneother user beam coverage area.
 38. The method of claim 27, wherein thefirst portion of the system bandwidth resources comprises contiguousportions of the system bandwidth resources.
 39. The method of claim 27,wherein the first portion of the system bandwidth resources comprisesnon-contiguous portions of the system bandwidth resources.
 40. Themethod of claim 27, wherein the first portion of the system bandwidthresources comprises multiple polarizations.